What Is Multi-Infarct Dementia?

Multi-infarct dementia (MID) is loss of brain function caused by a series of small strokes. A stroke (also called a brain infarct) occurs when the blood flow to any part of the brain is interrupted or blocked. Blood carries oxygen to the brain, and without oxygen, brain tissue quickly dies.

The location of the stroke damage determines the type of symptoms that occur. Stroke increases the risk of dementia as much as four to twelve times. The mechanism of this is not fully understood.

MID can cause the loss of memory and cognitive function and can initiate psychological problems. Treatment focuses on controlling the symptoms and reducing the risk for future strokes.

What Causes Multi-Infarct Dementia?

According to the National Institutes of Health, MID is the second most common cause of dementia in people over age 65 (NIH, 2012). Alzheimer’s disease is the most common cause.

MID is caused by a series of small strokes. A stroke (infarct) is the interruption or blockage of blood flow to any part of the brain. “Multi-infract” means many strokes and many areas of damage. If blood flow is stopped for more than a few seconds, brain cells can die from lack of oxygen. This damage is usually permanent.

A stroke can be “silent.” That means it affects such a small area of the brain that it goes unnoticed. Over time, many silent strokes can lead to MID. Large strokes that cause noticeable physical and neurological symptoms can also lead to MID.

Risk Factors for MID

MID generally occurs in people aged 55 to 75 years and is more common in men than in women.

Medical conditions that increase the risk of MID include:

atrial fibrillation (irregular rapid heartbeat that creates stagnation, which can lead to blood clots)

previous stroke(s)

heart failure

cognitive decline prior to stroke

high blood pressure

diabetes

atherosclerosis (hardening of the arteries)

Lifestyle risk factors include:

smoking

alcohol abuse

low level of education

poor diet with little to no physical activity

Recognizing the Signs of Multi-Infarct Dementia

The symptoms of MID may appear gradually over time, or may occur suddenly after a stroke. Some patients will appear to improve then decline again after more small strokes.

The early symptoms of dementia include:

getting lost in familiar places

difficulty performing routine tasks, such as paying the bills

difficulty remembering words

misplacing things

loss of interest in things you used to enjoy

personality changes

As dementia progresses, more obvious symptoms appear:

changes in sleep patterns

hallucinations

difficulty with basic tasks such as dressing and preparing meals

delusions

depression

poor judgment

social withdrawal

memory loss

How Is MID Diagnosed?

Doctors diagnose MID with radiological imaging and biochemical and cognitive tests. Each case of MID is different. Memory may suffer serious impairment in one case and only mild impairment in another. To gain an understanding of the damage done, doctors will use multiple tests.

Biochemical Tests

homocysteine (HCY): an amino acid produced as a by-product of eating meat. High levels may be associated with increased risk for atherosclerosis, heart attack, blood clots, Alzheimer’s disease, and stroke.

testosterone (T): a steroid hormone

17 beta-estradiol (E2): an estrogenic hormone

Mental Function Tests

Tests of mental ability include:

Barthel Index: assesses functional status

Fluid Object Memory Evaluation: looks at short-term memory

clock test: assesses your ability to recognize and set time

cognitive (SS-IQCODE) test: the “Informant Questionnaire on Cognitive Decline in the Elderly,” which uses a close relative to obtain information on a patient’s cognitive status

Ruling Out Other Causes of Dementia

Your doctor may also order tests to rule out other conditions that may cause or contribute to dementia, such as

anemia

brain tumor

chronic infection

depression

thyroid disease

vitamin deficiency

drug intoxication

How Is MID Treated?

Treatment is tailored to the individual. Both medicinal and nonpharmacological treatments are used.

Medication

There are two main types of medication used for MID:

Cholinesterase inhibitors treat memory loss, confusion, and problems thinking and reasoning. These include

donepezil

rivastigmine

galantamine

Noncholinesterase inhibitingmedications include:

memantine

nimodipine

hydrergine

folic acid

CDP-choline

Other medication options include:

selective serotonin reuptake inhibitors (SSRIs): antidepressants that may also help neurons grow and reestablish connections in the brain

calcium channel blockers for short-term cognitive function

ACE inhibitor anti-hypertensive therapy to lower blood pressure

Alternative Therapies

Herbal supplements have grown in popularity as treatments for MID. However, not enough studies have been done to prove a significant amount of success through their use. Examples of herbal supplements that are currently being studies for use in treating MID include

Be sure to discuss these supplements with your doctor before taking them, as they can interfere with other medications.

Nonpharmacological options for treatment include:

regular exercise to build muscle strength

cognitive training to regain mental function

rehabilitation for mobility issues

What Is the Long-Term Outlook for MID?

MID has no cure. While medications and cognitive training may help preserve mental function, the patient will continue to decline. The speed and advance of dementia varies. Some patients die soon after an MID diagnosis, and others survive for years.

How Can MID Be Prevented?

There is no evidence of any completely effective measure to avoid MID. As with many conditions, the best prevention is to take care of your body: